Q. What is adiabatic humidification? A. There are two basic ways to introduce moisture into air: Isothermal Humidification – the water vapor is dispersed in the air after having been created by boiling water. Isothermal humidification requires an external source of energy to change the state of the water. In the commercial HVAC world Isothermal… Read more »
Posts Categorized: Ask DAC
Ask Rick: Should I use a bypass damper on an Energy Recovery Wheel?
Q. Should I use a bypass damper on an Energy Recovery Wheel? A. We typically use a bypass damper around a energy recovery device for frost control and economizer. That is typical for Heat Pipes and plate exchangers. In the case of an Energy Recovery Wheel we typically slow the wheel down to minimum speeds… Read more »
Ask Rick: How much cross contamination occurs with an Energy Recovery Wheel?
Q. How much cross contamination occurs with the use of an Energy Recovery Wheel? Does exhaust air get mixed back into the supply air stream? A. Cross contamination refers to the amount of air that is leaked from one side of the wheel to the other. Leakage rates are significantly reduced by using higher quality… Read more »
Ask Rick: Why aren’t direct drive fans used on more applications?
Q. Why aren’t direct drive fans used on more applications? A. In Europe, 80% of commercial ventilation units sold today are equipped with direct drive fans. In The US, the industrial and heavy commercial fields have already recognized the benefits of direct drive fans. Reduction in maintenance has been the primary motivation. In HVAC applications… Read more »
Ask Rick: High Plume Dillution Fans | Is the motor out of the airstream?
Q. On the Strobic Air Tri-Stack Fan is the motor out of the exhaust airstream? A. Yes, the fan motor is outside of the exhaust airstream. This is true for Strobic Air and for all High Plume Dilution Fans (Laboratory Fume Hood Exhaust Fans).
Ask Rick: Pumped Glycol Systems | Where are Konvekta Systems manufactured?
Q. I have read about Konvekta systems. They are a Swiss company. Do they manufacture any parts of their system in the US? A. Most components are made in the USA; in particular, the Hydronic Module and its components (pumps, motors, valves, expansion tank, etc.) are made or are purchased from suppliers in the USA. The coils are still… Read more »
Ask Rick: When do you use a Desaturation Coil?
Q: In what applications do you recommend using a desat coil? A: In general, a desaturation coil (desat coil) will help in any application where the cooling coil is the last component in an air handling unit. The desat coil is one of several options which can provide the necessary minimal reheat so supply air… Read more »
Ask Rick: How does a freezestat work?
Q: How does a freezestat work? A: You should use a freezestat to protect your water coils from freezing. Rooftop units with water coils should always have freezestats, even if using a water/glycol mixture. Typically the heating coil would be upstream of the cooling coil. Usually the freezestat is attached on the leaving side of… Read more »
Ask Rick: Energy Recovery Wheels | Wheel off for Economizer?
Q. Is it ok to turn an energy recovery wheel off for economizer purposes? A. No, we do not recommend that. If an energy recovery wheel is stopped it’s flutes can clog if filters are not maintained properly. The wheel is self cleaning as it rotates through opposite air streams. It needs to run at… Read more »
Ask Rick: Heat Pipe Tilt Mechanism | When are they used?
Q. When are Tilt Mechanisms used on Heat Pipes? A. In the early heat pipes a tilt mechanism was used to shift the heat pipe from summer to winter use. It did this by physically lifting one end of the heat pipe. That allowed refrigerant fluid to run back to the warm side of the… Read more »